Even after about a century of development, most commercial fixed wing aircraft continue to be designed around the same core features including wings, a fuselage, control surfaces and engines. Although there have been numerous advances in aerodynamics, materials employed, power and efficiency of engines used, and other improvements in component design, the basic structure has remained roughly similar for quite some time. During this period, the largely cylindrically shaped fuselage has remained a recognizable and consistent feature of commercial aircraft.
Particularly for passenger airliners, the fuselage has typically been divided into separate decks. In many instances, passengers sit on an upper deck that is pressurized and is referred to as the cabin. The cabin is often separated from a lower deck in which cargo is housed. However, for some larger sized passenger airliners, multiple passenger decks may be employed over at least a portion of the cabin area.
In the past, the use of multiple decks in the cabin area has only been employed on the largest airliners. However, even on these relatively large airliners, due to size and design constraints, moving from an upper level to a lower level (or vice versa) in a multiple deck airliner has typically been facilitated by the provision of staircases or ladders. Some airliners have also employed cart lifts to facilitate movement of carts between levels. Having multiple decks in the cabin area can create complications for boarding and deplaning. For example, accessibility of certain areas of the plane (i.e., those accessible only via using stairs or ladders) may be restricted based on age or health of the passengers. Furthermore, movement of carry-on luggage up and/or down stairs and ladders can be difficult for even healthy adults in some cases. Stairs or ladders also typically end up being a choke point that slows down boarding or egress.
Accordingly, it may be desirable to develop alternative ways of arranging the layout of the interior of the fuselage to overcome some of the disadvantages described above.